1. Field of the Invention
The invention pertains to an arrangement for receiving a rotating body, in particular a grinding wheel or a high-speed grinding wheel, in a centered and axially fixed manner, as well as a corresponding adapter for clamping a rotating body in a radially and axially fixed manner.
2. Discussion of the Background
When carrying out cutting procedures, it is required to connect a rapidly rotating body with a spindle or another tool carrier, e.g., a tool system module or a workpiece carrier, in a centered and axially fixed manner. This problem occurs particularly with high-speed grinding wheels that operate at peripheral speeds in excess of 100 m/sec. Grinding bodies of this type are formed of high-strength steel disks that are provided with a diamond coating or a CBN (cubic boron nitride) coating, with a trimming of such grinding bodies no longer being carried out. These rotating bodies must be coupled to the drive spindle in such a way that they rotate with high concentricity. One additional problem consists of maintaining as low an eccentricity as possible during the clamping process, while still ensuring a secure axial fastening on the spindle.
In this context, several arrangements of the initially mentioned type have been disclosed. The most widely used solution consists of clamping a grinding wheel that is provided with a cylindrical recess in its center against a radial face surface of the carrier part, namely a cylindrical spike, with the aid of several clamping screws that are uniformly distributed over the circumference. In this case, the play of the clamping screws as well as the play of the centering spike in the central recess of the grinding wheel must be eliminated by means of relatively time-consuming assembly and adjusting procedures.
According to one additional known arrangement, the radial, centered clamping is realized with the aid of four clamping bodies that are respectively situated at an angle of 90.degree. to one another and can be adjusted in the radial direction such that the concentricity can be simultaneously adjusted in a precise manner during the clamping process. Although this arrangement makes it possible to exactly adjust the concentricity of the grinding wheel, a sufficient axial clamping cannot be easily attained in this manner.
It would be conceivable to realize an arrangement of this type in such a way that the receptacle opening in the rotating body, i.e., in the grinding wheel, is designed in conical fashion and that the clamping in an axially and radially fixed manner is attained by pressing the grinding wheel onto the axial centering spike of the hub part which has a complementary conical design by means of a clamping plate. In this case, clamping means that act in the axial direction, e.g., in the form of several clamping screws that are distributed over the circumference, are utilized. The respective heads of said clamping screws are braced on the clamping plate, with the threaded section of said screws being engaged with a part that is rigidly connected to the hub. However, one disadvantage of this variation would be the relatively complicated processing of the centering receptacle hole in the grinding wheel. Even in instances in which a very strict range of tolerance is observed, it is quite problematic to maintain the wobble within the desired narrow ranges of tolerance, in particular with grinding wheels that have a larger axial thickness.
There also exist solutions for arrangements of the aforementioned type which utilize the so-called expansion clamping technique. According to this technique, pockets that are uniformly distributed over the circumference and filled with a hydraulic medium are arranged within the region of the centering spike. These pockets are covered by a thin piece of sheet metal. A uniform centering of the attached grinding wheel is realized by pressurizing these pockets that are filled with a hydraulic medium. This technique makes it possible to adjust the concentricity of the grinding wheel in a very exact manner. However, this clamping technique also requires additional measures for fixing the grinding wheel to the hub with the least possible wobble. This means that this known clamping technique is very complicated and is associated with the additional disadvantage that special devices for generating the pressure re required.
U.S. Pat. No. 1,684,032 discloses a clamping device for positioning a rotating body on a carrier part in centered fashion. The carrier part comprises an axial centering spike that protrudes into a central receptacle opening of the rotating body and a radial collar that is situated adjacent to the axial centering spike. The rotating body can be axially pushed against the radial collar. An axial extension that can be elastically widened is arranged between the centering spike and the receptacle opening, with the inner contour of the axial extension corresponding to the outer contour of the centering spike and the outer contour of the axial extension corresponding to the inner contour of the receptacle opening. The axial extension is connected to a clamping plate so as to form an adapter part. In this case, the clamping plate has a smaller diameter than the axial extension. A central screw with different pitch sections is accommodated in the adapter part. This screw engages with a threaded hole that is arranged in the carrier part. The cylindrical outer surface of the axial extension can be radially pressed against the rotating body, while the axial extension is elastically widened by tightening the aforementioned screw.